Position indicator



1946. c. D. WILSON 2,392,209

' POSITION INDICATOR- Original Filed July 19, 1940 a, '42 7 8 /a /& a, l

Patented Jan. 1, 1946 UNITED STATES "PATENT OFFICE 2,392,309 (POSITIONinmca'ron Continuation of application Serial No. 346,388, July 19, 1940.This application March 13, 1943,

Serial No. 479,079

3 Claims.

This application is a continuation of my copending application SerialNo. 346,388, filed July 19, 1940; and the invention disclosed hereinrelates generallyto position indicators and more particularlyto the typeof indicator which is especially adapted to accurately measure therelative axial position or displacement of a rotor with respect to theassociated stator or casing.

The efliciency of a turbine decreases with increased axial clearancesbetween the stationary and moving blades and the usual practice is toconstruct large turbines so as to permit aslight axial adjustment of thespindle or rotor with respect to the stator in order to obtain the bestpossibleefiiciency during operation under varying conditions ftemperature and pressure. This construction necessitates the use of apositionor clearance indicating means which is capable of accuratelyindicating the relative position of the spindle or rotor with respect tothe stator. A common procedure in this connection is to employ anaxially movable rod or shaft which is provided with an axial micrometeradjustment, with an eccentrically-disposed end portion, and with a means'for' turning the rod about its lon gitudinal axis in order tosuccessively position the eccentrically disposed end of the rod inonposed relation with respect to plane reference surfaces on the spindleand stator and to effect an actual engagement of the eccentricallydisposed end portion with the reference surfaces by effecting an axialmovement of the rod. Another and somewhatsimilar procedure, which hasalso been used extensively, is to employ a rod positioned to extendparallel to the spindle axis which is provided with a plunger and aspring biasing means arranged to urge the end of the rod into engagementwith a plane and radially extending surface on the adjacent end of thespindle. A multiplying lever indicates the relative position of thespindle with respect to the casing and the end of the rod may bewithdrawn from engagement with the spindle by the operator and held inits withdrawn position by means of coacting retaining surfaces.

These commonly used procedures have not proven entirely satisfactory, asthe axially movable position indicating 'rod must of necessity bepositioned adjacent the end of the turbine spindle or rotor and as aresult the relative displacement. between the rotor and stator isdetermined at a point at which the temperature is relatively low.Consequently, the actual clearance between the moving and stationaryparts in the hottest portion of the turbine'cannot be determined by theknown types of apparatus previously mentioned. Furthermore, when theknown types of apparatus are used in connection with modern highpressure turbines, for exam- 5 ple, topping turbines in Which the steampressure adjacent the discharge end may be as much as 600 lbs. persquare inch, the force exerted on the end of the rod by the pressure ofthe steam renders an axial movement of the rod IQ and a determination ofthe degree of contact between the end of the rod and the opposedsurfaces on the spindle or stator extremely diflicult, if not impossibleand the results thus obtained highly inaccurate.

15. It is therefore an object of this invention to provide an improvedposition indicating means which will facilitate the determination of therelative position or displacement of one member with respect to anotherand which will entirely 2Q eliminate the aforementioned defects.

" Another object of this invention is to provide an improved positionindicating means which can be operatively positioned adjacent radiallyspaced or between axially spaced moving and 2 5 stationary parts in anypart of the machine thereby permitting an accurate determination of theclearance between stationary and moving parts in the highly heatedportion or portions of the machine.

Still another object of this invention is to provide an improvedposition indicating meansin that the relative position of two associatedmemhers is readily and accurately indicated or measured by the angularmovements of a rod about its longitudinal axis. l

'A further object of this invention is to provide an improved positionindicating means in that the relative position of two associated membershaving radially spaced reference surfaces can be readily and accuratelymeasured by means of an axially movable rod having thereon atransversely extending portion which is alternatively positionedopposite the reference surfaces on said members by an axial movement ofsaid rod and which is brought into contact with said surfaces byeffecting an angular movement of said rod about its longitudinal axis.

The invention accordingly consistsof the various features ofconstruction, combinations of elements, and arrangements of parts asmore particularly set forth in the appended claims and in the detaileddescription, in which:

Fig. 1 is a partialsectional view of the high pressure end of a turbineembodying the inven- 55 tion.

Fig. 2 is an enlarged side elevation of that portion of the indicatingdevice shown in Fig. 1 whic is outside of the turbine casing;

Fig. 3 is a plan view of the device shown in Fi 2;

Fig. 4 is aview of the right-hand' end of the.

device shown in Fig-L 2;

Fig. 5 is a sectional View taken on Fig. 2;

Fig. 6 is a view similar to Fig. 4 showingth position to which theindicating arm must-be lin v-v of rod member 2i extends is counterboredto pro vide the packing space 29 and is internally threaded to receive apacking nut 3|. The inner end of the bore in the supporting structure l9through which the rod member 2| extends is also counterbored-= toreceive? an. annular bearing member.- 3 2i which. is held in; place; byaiset screw 33. The rod member 2| immediately above the supportingstructure I9 is provided with a trans,-

verse bore 34 into which is partially inserted a Iaterallyextending pin36 adapted to engage the moved before an axial adjustment. ofthe'meas- 7uring device can be effected; r

Fig. 7 is another view similar to Fig.4 showing 15,

the position to which the indicating arm is moved 7 after the axialadjustment of; the measuringdevice has been efiected; and 1 Fig. 8 is aview of a modified construction; Referring to Fig. 1, it is seen thatthelmeasure ing device I is shown, for purposes of illustra:

tiOn, asappliedftoa turbine- Z-having acasing-or stafltojr'i and aspindle or rotor 41 The-spindle. andjcasing; are pr videdwith coactingmoving and stationary blades Band 1; respectively; to which a workingfluidis suppliedthrougha nozzle structure 8, v The spindle isalsoprovidedwith a dummy pistonstructure or cylinder- 9 having thereiniaplurality of annular sealing grooves l I whichcoact with complementarysealing projectionslll on a stationary'block l3-mounted on the.interior; of the casing 3'so as" to form therewith alabyrinth seal; Thespindle, and casing are also provided" .with' coacting portions oneither side of thedummy piston structure}! which form the additionallabyrinth sealing structures I4 and IB disposed in axiallyspaced'relation with respect 5 to oneahother andjwith respect to thedummy piston structured. The sideof the dummy-piston structure 9..Whichisjadjacent thesealing structure Hifand, thecorresponding side oftheingand bearing, structure [9, a rod or shaft'memher; 21. which ismounted in the structure I l 9 for axial-and .forjangular movements.withrespect to its longitudinalaxis, a. lever 22., and a pair I of;links 2 0p 'operatively. connecting the leve 2 2: with theconne'ctor' 23which in turn isf connected with the rod member 2.! for efiecting axialmoyements of the member. 2L in responselojmove'mentsof the lever 22, anda] laterally extending arm 24 which is rigidly securedto ftherodmember2| by means of thefclampingfstructuiie 26 and which serves foreffectingangularfmovement s of. therod member 2]. The end of the rodv..m,emberZl'opf posite that to which Qisattachedthe connector 23 is provided-withvlaterally extending portion I or lro gfi n v ei e'reon jicontactinportion op-surface 28 adapted for; engagement with the referenc surfacesl1 and. I8 on thejrotor. and stator, respectively. In other words; thereference; surfaces 1 I and I 8} needhot lie in the same rotonand 1stator; determined whilethe turbine is;

plane, and all that islnecessary inthis respectis that the; transverselyextending parton portion 2'! be of greater; radial length,asmeasuredjromthe; axis of; rod' 2 l.- than is' the; distance between he idea theod'ancuh a thest ramm d of said surfaces. The outer end of the bore in thesupporting structure l9 through which" the packing; nut;3l., andgtherebylimit the inward axial movementofjthe rod member 2|.

The; supporting; Structure '19 has removably secured thereto. as bymeans of the bolts 31, a laterally,extending rigid member 38 which isgenerally rectangular in shape when viewed in plan as shown in Fig. 3.The outer free end or edge of themember 38 is of a'rcuate shape as shownin Fig. 3 and is provided with a. scale 3 9, as shown in Figs. 4; 6 .and7'; Thetransverse cross}?? na o u ti of" hemem er 3' jW ich has:depending side flanges 41 is of inverted U shape. form, asclearlyfindicated" by Figs. 4, '6 and 'Z; The arm 24, whichlis securedtqthe rod member 2i and which is approximately coextensive in lengthwith the member 3 8 extends adjacent and in overlying relation withrespect to the] member 3 8; The freeend of the arm 24 is- ;provided witha pointer 42 which is disposedinindicatingrela tion with respect'to thescale 39 on the,member 38, and with a transversely. extending opening43' adapted to receive the laterally extending arm 440 1. t e oc g mame.v fifii h' c n h sill istration is. rigidly securedjto the, top surfaceof: themember 38 by any s. h c ping ut" .1;

The lever 22; comprises, best seen in Figs. 3, ,4. Ggandfl, va piv tpin. .4 8 ;having its ends rotat'. a y" m unted maim d bear ngs 9, n nejin. the pa r. of upstan n nd ppcs t y po ed. ars. 5L which,arefboltedjtothe side flanges of,,the.

member 3.8 ladjacentitspointoi connection to the supportingstru turel9;.anair f laterally, spaced. parallelarms-fil secured to and extendingtrans v rs ly 'fronijthepivot ipiii and hav n It free endsjpivotally.witntnepairz of links meme iififnare. pivot-ally' onne ted m me.opposite. sides of the connector 23, and; anoppositely ex; tending. arm53, which .is secured}. to. and..extends transversely. from .the,portionpf ,the pivot pin 48: intermediate the. arms. 52 This arrangementprovidesinj eflect a lever, having an operating; handle portion 53 and abifurcated; end portion. 52 wh his pivotally connectedwiththeli s. 20.Thejha'ndle,portionj53. 0.1. the lever 2, is provided. intermediate;itspoint. of pivotali con]: nectioh withthe bars 5l andits freeendlwitha dependingpivotally .clonnected link, 5.4, having. as. seeninFigs'.4, 6- and 7',.,'a}.later'al1y 'ofiseti lower.

iportion having in one.dg.e; thereofia pair, of Jon:

gitudinallyv spaced notches .56 adaptedg'to receive the pm 511' onptheadjacentlside-fiancefll'. of ;.the. member 38; Thearrangem'entissuchlthat when. the rod. 21 ispositionedwithjts measuring; pro ectionZfl oppositethe. reference'surfacel'] on ,the. rotor; the pinv 5.1..enters tlie.lowennotch, 56 in, the linkjiand thatavhehlt eprbjeetiorlzlisdiss posed, opposite. the i reference. surface] .-I 8, onthey stator block .I 3, thepin .51, enter snthe ,uppernnotch sejir itheinkja." 'Iflie 11m; 5411s disengagedfrgmr the, 1 311151. by the opclfatqfmoying the linle angue. lariwm a aunter lgckwiseqirec ioaas e Ei 's.:;..and' .anqr nsasemesws" ffected it r by the operator-orbygravi-tyactiomwhen'thejtaple me ns su h a link is subsequentlyreleased. However, if preferred, a positive biasing means'of any desiredtype'may be employed.

The connector 23 comprises, asbest seen in Fig. 5, a hollow, open-endedand internally threaded block member 58 having opposite laterallyextending exterior projections 59 to which the links 20 are pivotallyconnected, a threaded plugmember 6| closing its outer end, and athreaded annular, plug member 62 through which the rod 2| is adapted topass, closing its inner end. The outer end surface of the rod 2| isprovided "with a slight recess 63 of spherical .form adapted'to providea seat for the spherical ball 64. The outer end portion of the rod 2| isexternally threaded and has secured thereto an internallythreadedannular collar member 66 adapted to engage the adjacent surface of theannular plug member 62. The rod 2| and the connector 23 are assembled byplacing the annular plug member 62 on the rod 2|, then securing theannular collar 66 on the end of the rod, then inserting the end of therod into the interior of the hollow block member 58 and screwing theannular plug member 62 in place, then placing the ball 64 in the seat 63on the end of the rod 4|, and then screwing in place the plug member 6|.tive and a substantially frictionless connection between the rod 2| andthe connector 23 which permits a slight degree of angular movementbetween the said rod and connector since the internal diameter of theannular plug member 62 is greater than the diamete of the rod 2| asshown.

The position indicator shown is partially assembled in the selected partof a separable stator structure of usual construction (not shown) beforethe stator structure is assembled by boring the selected part to receivethe supporting structure l9, by inserting the rod 2| through the borefrom the interior side of said part, by sliding the said supportingstructure |9 on the outer end of said rod and into said bore, bysecuring the supporting structure H! to the stator part, and byinserting the pin 36 in the rod 2| so as to retain the rod in theapproximate position, as shown in Fig. 1 with respect to the supportingstructure I 9. The remaining portions of the position indicator arepreferably assembled in the obvious manner.

after the stator structure has been completely assembled. However, ifdesired, the external diameter of the supporting structure may be madesuch that the rod 2| can be inserted through the bore from outside thestator structure in which event the position indicator can be entirelyassembled after the turbine is otherwise ready for operation.

The relative position of the spindle or rotor with respect to the statoris readily determined by the operator, assuming the various parts are inthe position shown in Figs. 1-4, inclusive, by moving the indicator arm24, if necessary, so as to set the pointer 42 on the scale 39 in thezero or base position, then moving the indicator arm 24 in acounterclockwise direction as viewed in Fig. 4 until the contactingportion 28 of the projection 21 engages the reference surface I1 andreading the position of the pointer 42 on the scale 39, then moving theindicator arm 24 in a clockwise direction, which moves the projection onthe rod 2| away from the reference surface l1, until the end of the arm24 is free of the locking projection 44 as shown in Fig. 6, then movingthe link 54 in a counterclockwise direction as viewed in Figs. 1 and 2,thereby disengaging the link 54 from the pin 51, then moving theadjacent end of the lever This construction provides a posi- 22 downwarduntil the pin 51 engages the upper notch 56 in the link '51 whichmovement of the lever 22 effects through the links20 and the connector23 on outward axial movement of the rod sufficient to bring theprojection 21 opposite the reference surface |6 on the stator block l3,then moving the indicator arm 24 in a counterclockwise direction, asviewed in Fig. 7, until the pointer is again in its zero or baseposition, as shown in Fig. 7, and then continue moving the indicator arm24 in the counterclockwise direction until the contact portion 28 of theprojection 21 engages the'reference surface l8 and again reading theposition of the pointer 42 on the scale 39. The difference between thetwo readings just mentioned accurately measures with respect to the zeroor base position selected, the angular movement of the indicator arm 24and rod 2| which is necessary to'engage the contact portion 26 on theprojection 21 or rod 2| with the reference surfaces l1 and I8 on theturbine rotor and stator, respectively. Consequently, the abovementioned procedure accurately determines the position of the rotor withrespect to the stator at the time the readings are taken.

The actual measurement of the relative position of two objects iseffected solely by angular movements of the rod 2| and consequently thedegree of pressure within the chamber or compartment in which thereference Surfaces are located and into which the coacting end portionof the rod 2| extends in no manner effects the determination of thedegree of contact between the rod and the said reference surfaces.Moreover, the indicator arm 24 can be readily made of sufficient lengthwithout rendering the device cumbersome or unwieldy to effect therequisite degree of multiplication which is necessary for obtainingextremely accurate readings of the slight angular movements of the rod2|. Furthermore, since the rod 2|, the projection 21 and contactingportion 28, and the arm 24 are in effect an integral structure, theindicating device is entirely free from multiplying lever arrangementsand the like which are always conducive to some degree of lost motionand inaccurate results.

Referring to Fig. 8 in which like numerals are used to designate thesame or similar parts, it is seen that this modification differs fromthat shown in Figs. 1-7, inclusive, in that the plane parallel referencesurfaces I1 and |6 on the rotor and stator, respectively, arevoppositely disposed instead of being radially spaced as shown in Fig. l;in that the lateral projection on the rod 2| is provided with acontacting roller 61 instead of the contacting portion 28; and in thatthe rod 2| is mounted only for angular movements about its longitudinalaxis and that therefore the connector 23, the links 20, the lever 22,the notched link 56, the pin 51, the opening 43, and the look ingstructure 44, 46 are omitted.

'Measurements may be taken with this modified construction simply bymoving the indicator arm 24 so as to set the pointer 42 to its zeroposition midway between the ends of the scale 39, then moving the arm 24from said midposition in a clockwise direction until the roller 61engages the reference surface l8 and reading on the scale 39 thedistance the pointer 42 has been moved from its zero position, thenmoving the arm 24 in a counterclockwise direction until the roller 61engages the reference surface l1 and again reading on the scale 39 thedistance the pointer 42 has been moved from its zero position. Thedifference between these two readings is, as prevlouslystated;connection with the description? of. Figs, 1-7-,,- inclusive, anacourateimeasurement; of the relative position' of? the rotor 4- andql estator- 3. In: thisconnection it may be welbto point out--that1whileinthis modified construe-e tion the rod? 2|- and; the indicating man 24'are f-rictionally held in the supporting andbearing I structure 19'against accidental turning: movement, it: may bev desirable in someapplications to provide a positive latch meanstoperform this: function;J,

Themo'dified construction illustrated in- Fig. 81 provides all of theadvantagespreviouslypointed out in connection with Figs; 1-7, inclusive;and while it maybe preferred for particular applications; generallyspeaking, it is'not quite as satis' factoryadue to the fact thattheroller: may not Wear uniforml whichi would introduce inac0u-- racieswhen theiwear'becomes: appreciable, unlessthe same part of the roller"always engages: both of. the reference surfaces; 1

Bothforms of the apparatus are herein shown and described by way: ofapplication as applied to an end portion ofa turbine: inwhich thetemperature is relatively high and the: pressure is relatively low, but it.should beunderstood that measuring: apparatus embodying this inventioncan be readily positioned inoperative relation adjacent to radiallyspaced" or between: axially spaced'moving andstationary-parts inthe-highly heated and'high pressure portions of themachine and readingsreadily taken withoutin anyman ner effecting the accuracy of the resultsthus ob tained'; The invention isapplicable for measuring or'determiningthe rela'tive positions of any aaeaaoa:

said part eine of er a r i as meas'? V ured from? thelongitudinal; axisof said rod than the distance between theside of-saidrod and thefarthest removed of said referen'cesurfaces, and

1 meansoperative when said rod isin eithe'rof s'aidtwo-positions toeifect asufiicientangular move! mentaof; said-rod to engage said: partwith the oppo tely disposed one of said reference surfaces.

2; indicator for measuring the relativeax? ial' position of a rotatingmember with respect to a coaoting. stationary member presenting areference surface. which is radially spaced from a referencesurface'onsaid-rotating. member comprising a rod having thereon a laterallyextending:

- part}. means supporting said rod for longitudinal movement adjacent.said reference surfaces. and for angular movement about its longitudinalaxis} means including a lever for effecting a longitudinal movement-ofsaid rod and for locking said rodin: either of two positions, in one ofwhich said p'artis positibnedLopposite-the reference surface. onsaidrotating member andlin the other of which said part is positionedopposite the reference surfaceon said stationary member, said'pa'rtbeing of greaterradial length as measured from thelongitudina-l axis ofsaid rod" than theldis be further" understood that; it is; not desired:to

limit the invention to: the exact mode of oper:

1. Anindicator for measuring'the relative axial position: of a rotating:member withres'pect to a. meeting stationary member presenting areference' surface' which. i's radia'lly' spaced from a refere'n'ce"surface on said rotating member-comprising: a rod having thereon alaterally extending part; means supporting said; rod for lo'ng'iitudinal movement alrll'ace'ni', saidreferehcef suitfacesa'ndforangular'm'oveinent aboiit it'slo'ngi; I

tildilfial axis; ll'leahs -inbllidil'lga lVe-i for effectinglongitudinalniovei'ne'iit of said rodand forlook;

ing said rod in either of -t'w'o po itions, in one of which said part 7is positioned I opposite the reference surface on-said rotating memberand inth'e other of which said pa'rti's' positioned opposite thereference surface on s'aidstationary member, 7

tance between the side offsaid rod andthe farthest removed ofsaidreference surfaces, means operative toprevent longitudinal movement ofsaid rod from either one of said twopositions to the other whensaidipart engages or is disposed in proximity with respect to theoppositely disposed one of' said reference surfaces",and means"operative when said rod is in either of said two positions to efiect asuificient angular movement 7 of said-rod toengage saidpartwithth'eopposite 1y disposed one ofsaid reference-surfaces 3;An-indicator for measuring the relative axial: position of a. rotatingmember with respect. toa coacting. stationary member presenting" areference surface which is radially spaced from a reference surfaceonsaid rotating member com, prising a rod having thereon a, laterallyextending part,v means supporting said rod for longitu dinal movement'adjacent said reference surfaces andfor angular movement about. itslongitudinal axis; means foreffectinga longitudinal movement of 7 saidrod to alternatively position saidpart lop posite the said referencesurfaces; said part be-ling' ofgreater radial length as. measured fromthe longitudinal axis of said rod' than the distance. between the sideof; said rod and the. far thestremoved of said reference surfaces}.means operative to prevent av longitudinal movement of said rod whensaid part engages or is disposed in proximity with respect to either ofsaid re erence surfaces; and means forefiecti'ngj a. umcient angularmovementof' said rod to" engage 'saidpart withtheoppositely disposed oneof 's'aid referenoe-surfaces.---

cnARrns DIYWILS'O'N; j

